Methane monitor sensing system

ABSTRACT

A methane monitor is disclosed that has at least one removable and replaceable sensor interchangeably inserted into a receptacle located on the outside wall of the monitor. A thumb operated latch attached to the sensor is used for connecting the sensor into the receptacle.

This invention relates to part of a methane monitoring system used onmining equipment to prevent operation of the equipment in heavyconcentration of methane gas. My invention has special reference to thepart of the system that detects or senses the gas in the air of themine.

The objects of this invention is to provide a better methane monitorsensor system providing a much quicker and easier replaced sensor byusing a thumb-pressure operated latch with plug-in connections forelectrical contact; also make troubleshooting the methane monitoringsystem easier by inserting a test circuit with an indicator light toshow when the sensor is good or bad; and to cut down on down-time on apiece of mining equipment by having a built in spare sensor with quickand easy switching from one sensor to the other.

Other advantages and their adaptability to work on all monitoring systemcan be seen from examing the attached drawings in which:

FIG. 1 is a top view of my sensor housing.

FIG. 2 is a front view of my sensor housing.

FIG. 3 is a side view of the sensor element used in my invention.

FIG. 4 is a schematic view including the circuit.

As shown in FIG. 1, FIG. 2 and FIG. 4, my methane sensor system has 2complete and seperate methane sensors (1). Each of these has inside, asensing element and a compensator element coming to contact with themale plugs (5). The female receptacle (12) is located in the sensorhousing (7). This is held in by screws from inside of the housing (7).The sensor (1) is held into place by a spring-loaded latch (8). FromFIG. 1 you can see two indicator lights (3) which are used to indicate agood or bad sensor when the test button (4) is pushed. The male contacts(5) on FIG. 3 are plugged into the female recetacle (12) and makeelectrical contacts through metal contacts (6). The sensor (1) is heldinto place by a hook (13) on the bottom which fits into the bottom slot(9). The top of the sensor (1) is held by a spring latch (8) which isthumb-operated. The entire unit is wired to the methane monitoringdevice by a cable (10). Access to the inside of the housing (7) is by athreaded lid (11).

As you can see from FIG. 2 and FIG. 3 the quick change sensor (1) willeliminate the job of taking the sensor housing apart to change sensors.When a bad sensor is detected it can be unplugged and another insertedinto it's slot with very little trouble and a very short time. In thepresent monitors most sensor assemblies have to be removed from themachine to change the sensor elements.

Also you can see from FIG. 1, I have inserted a test button (4) which iswired so that when the button (4) is pushed in, the circuit to thewheatstone bridge, which all monitoring systems employ, is broken andthe circuit current is directed through both sides of the sensingelements and through the indicator light bulb (3) or a LED can be used.Therefore when you have a good sensor with both elements conducting, thecurrent will pass through them and the indicating lights (3), causingthe lights to burn. But if either element is open the current cannotflow through the light thus the bulb will not burn indicating an opensensor. Because nearly all monitoring systems are different I cannot gointo detail for each system, however the idea can be applied to allsystems.

Also from FIG. 1 and FIG. 2 you can see I have incorporated a built inspare sensor (1) with a switch (2) to switch operation from one sensorto the other sensor. I have done this by simply taking a toggle switchwith as many poles as needed (some are 3 wires some are 4 wires). The incoming wires from the cable (10) are wired to the common posts of theswitch (2). One sensor (1) is wired to the normally opened side, theother hooked to the normally closed side of the switch. They are hookedso that #1 sensor is in operation when the toggle switch is pointed inthe #1 position on the sensor housing as shown in FIG. 1.

I believe that this sensing system is superior to present models and Ibelieve I have demonstrated this in this application.

I claim:
 1. A monitor for the analysis of methane comprising at leastone removable and replaceable methane sensor adapted to be insertedinterchangeably into at least one receptacle located on the outside wallof the said monitor by plugs attached to said sensor, which enables saidsensor to be connected to a circuit means having a switch means forconnecting one of the said sensors at a time to the said circuit meansthat illuminates a designated bulb attached on the monitor when the saidsensor is correctly operating, and with a thumb operated latch attachedto said sensor for latching said sensor into any of the saidreceptacles.
 2. A methane monitor as in claim 1 with at least onemethane sensor as described herein that varies in its degree ofsensitivity and can be interchangeably inserted into each and any saidreceptacle located on the outside wall of the said monitor.